• 한국작물학회지
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• 제50권4호
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• pp.265-267
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• 2005

Study on effectiveness of Bradyrhizobium japonicum on soybean [Glycine max (L.) Merr.], local cultivar 'Sathiya' were carried out in the garden soil of Trib-huvan University. Different parameters like nodulation, chlorophyll content in fresh leaves and growth of plant in inoculated and uninoculated plant was studied. Pot experiment was conducted in the green house to evaluate the effectiveness of B. japonicum on soybean. It was observed that B. japonicum inoculation increased the number of nodules, shoot length of plant and total chlorophyll content in fresh leaves of soybean plant. However, root length was decreased in all inoculated plants.

• Applied Biological Chemistry
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• 제40권5호
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• pp.438-441
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• 1997

칠곡통의 식양질 논에서 답전윤환시 밭작물로 콩을 재배했을 때 Bradyrhizobium japonicum의 밀도변화와 토양 이화학성과의 상관관계를 조사하였다. B. japonicum의 서식밀도는 계속 논이용구에서 $10^1cells/g.soil$ 수준이었고 답전윤환구에서는 $10^1cells/g.soil$ 이상 수준이었다. 그리고 시비수준별 균주 밀도는 무비구가 관행시비구보다 2년주기 윤환시 1.9배, 3년주기 윤환 및 4년연속 밭이용시는 10배가량 높은 수준이었다. 토착 B. japonicum 밀도변화는 토양의 유기물함량$(r=0.83^*),\;Ca/K(r=0.74^*)$ 및$(Ca+Mg)/K(r=0.72^*)$와 정상관 관계를 보였고 토양경도와는 부의 상관관계(r=-0.73*)를 보였다. 그리고, 계속 논이용구 대비 답전윤환구에서의 B. japonicum 밀도증가는 질소고정잠재능의 증가로 이어졌다.

• 한국토양비료학회지
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• 제35권1호
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• pp.12-26
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• 2002

근류형성에 의한 생물학적 질소고정기능을 갖는 여러종의 근류균을 대상으로 분자생물학적 계통 분류의 기초자료를 얻기 위하여 Azorhizobium, Bradyrhizobium, Mesorhizobium, Rhizobium, Sinorhizobium 속의 33 균주에 대한 ITS 영역의 염기서열을 이용한 계통 분류가 이루어 졌다. 이들 균주중 대부분의 균주는 한 종류의 ITS 영역을 가지는 반면, 일부균주는 2개의 서로 다른 ITS 염기서열을 가지는 것으로 나타났다. 실험에 이용된 모든 균주들간의 ITS 영역의 염기서열 상동성은 28 - 95%로 매우 변이폭가 컸으며, 이들 염기서열의 계통 분석에 의하면 4가지 그룹으로 구분되었다. Sinorhizobium 속의 모든 균주 및 Rhizobium giardinii 는 그룹 I으로 구분되었다 그룹 II는 R. giardinii를 제외한 모든 Rhizibium 속의 균주를 포함하고 있으며, 계통수의 topology는 매우 불안정한 것으로 나타났다. 특히, R. radiobacter와 R. rubi는 계통분류학적 위치가 불명확한 것으로 나타났다. Bradyrhizobium 속의 균주는 Azorhizobium caulinodans 와 함께 그룹 III로 구분되었고, 그룹 IV는 Mesorhizobium 속의 균주로 이루어 ㅈ다. 특히, Mesorhizobium 속균주의 ITS 영역의 염기서열 상동성이 높게 나타났다.

• Journal of Microbiology and Biotechnology
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• 제5권2호
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• pp.110-113
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• 1995

Transposon Tn5 was used to induce random insertional mutations in Bradyrhizobium japonicum, a soybean endosymbiont. By genomic Southern blot analysis, transposition events were found to have occurred randomly throughout the B. japonicum genome. After screening 3, 626 mutants by auxotrophy test, a histidine auxotroph was isolated. Upon plant infection test, the His mutant showed a 3~4 day delay in nodule formation.

• Journal of Microbiology and Biotechnology
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• 제5권4호
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• pp.241-243
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• 1995

A lipopolysaccharide (LPS) defective mutant of Bradyrhizobium japonicum was characterized in terms of its cell surface hydrophobicity (CSH). By monitoring the kinetics of adhesion to hexadecane the LPS mutant was found to be far more hydrophobic than the wild type strain; the removal coefficients were 4.65 $min^{-1}$ for the mutant, as compared with only 2.40 $min^{-1}$ for the wild type. The possible role of cell surface hydrophobicity of B. japonicum in nodulation process is discussed.

• Journal of Microbiology and Biotechnology
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• 제15권6호
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• pp.1280-1285
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• 2005

Using the nodY::lacZ fusion system in Bradyrhizobium japonicum USDA 110, 22 flavonoids, which have structurally different features, were tested to define the role of the substituted functional groups as an inducer or inhibitor for the nod gene expression. A functional ,group of 4'-OH on the B-ring and the double bond between 2-C and 3-C on the C ring were required to induce the nod gene expression in B. japonicum USDA 110. In the case of isoflavones, the 4'-methoxyl group, which blocks the open 4'-OH functional group, did not significantly lower inducing activity, as compared with isoflavones with 4'-OH. However, all flavonols tested, which have a 3-OH functional group on the C-ring, did not induce, but inhibited the nod gene expression. Flavone, 7-hydroxyflavone, and kaempferol (5,7,4'-trihydroxyflavonol) at $1\;{\mu}M$ concentration significantly inhibited the nod gene expression induced by 7,4'-dihydroxyflavone. However, 7-hydroxy-4'-methoxyflavone at $1\;{\mu}M$ concentration showed a synergistic effect with genistein and 7,4'-dihydroxyflavone on the induction activity.

• Journal of Microbiology and Biotechnology
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• 제12권5호
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• pp.826-828
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• 2002

In our previous studies, we have cloned and characterized a gene region from Bradyrhizobium japonicum ,which is involved in the synthesis of lipopolysaccharide (LPS). In this study, we have expanded the sequence analysis of the region and found an additional open reading frame (orf), which appeared to be divergently transcribed from the rfaF gene. Sequence alignment of the orf revealed a significant similarity with rfaD genes of Salmonella typhimurium , Escherichia coli, and Neisseria gonorrhoeae. These genes encode a heptose-6-epimerase, which catalyzes the interconversion of ADP -D -glycerol-D-manno-heptose to ADP-L-glycero-D-manno-heptose. This divergent organization of the rfaF and rfaD genes is different from that of other Gram-negative bacteria where two genes form an operon. A rfaD- mutant of E. coli was successfully transformed with plasmid constructs containing the rfaD gene of B. japonicum. Novobiocin sensitivity test showed that the rfaD gene from B. japonicum could complement the rfaD mutation in E. coli, which confirms the functionality of the cloned B. japonicum gene.

• Journal of Microbiology and Biotechnology
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• 제15권3호
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• pp.656-659
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• 2005

Small peptides synthesized by nonribosomal peptide synthetases (NRPSs) genes are found in bacteria and fungi. While some microbial taxa have few, others make a large number and variety. However, biochemical characterization of the products synthesized by NPRS demands a great deal of efforts. Since the completion of genome projects of numerous microorganisms, the numbers of available NRPSs genes are being expanded. Prediction of the peptides encoded by NRPS could save time and efforts. We chose the NRPS gene from Bradyrhizobium japonicum as a model to predict the peptide structure encoded by NRPS genes. Using computational analyses, the domain structure of this gene was defined, and the structure of a peptide synthesized by this NRPS was deduced. It was found that it encoded a tripeptide consisting of proline-serine-phenylalanine. This method would be helpful to predict the structure of small peptides with various NPRS genes from the genome sequence.

• Applied Biological Chemistry
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• 제41권3호
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• pp.247-252
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• 1998

콩 재배시 근류균의 합리적 이용을 위한 기초자료를 얻고자 남부지방의 평야지 밭토양과 논토양, 산간지 밭토양에 분포한 토착 Bradyrhizobium japonicum의 질소고정 잠재능을 상호 비교, 분석하였다. 토착 B. japonicum의 밀도는 산간 밭토양에서 $5.7{\times}10^4\;cells/g.soil$ 로 가장 높았고, 다음으로는 평야지 밭$(5.0{\times}10^4\;cells/g.soil)$, 평야지 논토양$(4.0{\times}10^3\;cells/g.soil)$ 순이었다. 콩 개화기의 지상부 건물생산력과 수확기의 종실수량은 서로간에 고도의 상관관계$(P{\leqq}0.001)$를 보이면서 두 성분 모두 평야지 밭 >산간지 밭 > 평야지 논토양 순으로 높았는데, 평야지 밭토양 중에서는 남해토양과 선산토양이 건물생산면에서, 김해토양은 종실수량면에서 각각 우수하였다. 콩 개화기에 조사된 근류수와 근류무게의 물질생산 기여도는 지상부 건물중의 경우 근류수$(r=0.383^*)$ 보다 근류무게가$(r=0.439^*)$ 더 높은 값을 보였으나 종실수량에서는 근류무게$(r=0.449^{**})$ 보다 근류수가$(r=0.505^{**})$ 더 높은 값을 나타내었다. 근류무게당 지상부 건물중과 종실수량 성적은 평균적으로 단원콩에서 보다 남해콩에서 각각 1.7배와 1.4배 높은 변이계수를 보였다.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1994년도 한국생물과학협회 학술발표대회
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• pp.114.1-114
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• 1994